Unpublished paper, 'A system of train-signalling, by which also disabled trains may telegraph for assistance without the aid of portable apparatus' by Charles Walker Walker explains that 'in the early days of telegraphy, messages were sent and trains were signalled on the same wires, [and] no facilities existed for reducing the apparatus employed for the latter purpose, to a simple form. The case is now becoming different, special wires being largely devoted to train signals'. He describes a system of electromagnets and bells which can be used in train signalling. Includes one page of figures and photographs of Walker's bell system. Subject: Engineering Received 9 March 1857. Read 19 March 1857. Whilst the Royal Society declined to publish this paper in full, an abstract of the paper was published in volume 8 of the Proceedings of the Royal Society as 'A system of train-signalling, by which also disabled trains may telegraph for assistance without the aid of portable apparatus'. 9 March 1857